From e9780ea599567c7c94aa595d51eb5818511044ca Mon Sep 17 00:00:00 2001
From: mrg <mrg@ucsc.edu>
Date: Thu, 11 Jun 2020 15:03:36 -0700
Subject: [PATCH] Add non-preferred directions for channel routes

---
 compiler/base/hierarchy_layout.py | 17 ++++++++++++++---
 compiler/modules/bank.py          | 11 +++++++++--
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/compiler/base/hierarchy_layout.py b/compiler/base/hierarchy_layout.py
index 244d7842..4b6c044d 100644
--- a/compiler/base/hierarchy_layout.py
+++ b/compiler/base/hierarchy_layout.py
@@ -1043,7 +1043,8 @@ class layout():
                 mid = vector(pin.center().x, trunk_offset.y)
                 self.add_path(self.vertical_layer, [pin.center(), mid])
                 self.add_via_center(layers=layer_stack,
-                                    offset=mid)
+                                    offset=mid,
+                                    directions=self.directions)
 
     def add_vertical_trunk_route(self,
                                  pins,
@@ -1083,7 +1084,8 @@ class layout():
                 mid = vector(trunk_offset.x, pin.center().y)
                 self.add_path(self.horizontal_layer, [pin.center(), mid])
                 self.add_via_center(layers=layer_stack,
-                                    offset=mid)
+                                    offset=mid,
+                                    directions=self.directions)
 
     def create_channel_route(self, netlist,
                              offset,
@@ -1146,7 +1148,8 @@ class layout():
             overlaps = (not vertical and x_overlap) or (vertical and y_overlap)
             return overlaps
 
-        if not directions:
+        self.directions = directions
+        if not directions or directions == "pref":
             # Use the preferred layer directions
             if self.get_preferred_direction(layer_stack[0]) == "V":
                 self.vertical_layer = layer_stack[0]
@@ -1154,6 +1157,14 @@ class layout():
             else:
                 self.vertical_layer = layer_stack[2]
                 self.horizontal_layer = layer_stack[0]
+        elif directions == "nonpref":
+            # Use the preferred layer directions
+            if self.get_preferred_direction(layer_stack[0]) == "V":
+                self.vertical_layer = layer_stack[2]
+                self.horizontal_layer = layer_stack[0]
+            else:
+                self.vertical_layer = layer_stack[0]
+                self.horizontal_layer = layer_stack[2]
         else:
             # Use the layer directions specified to the router rather than
             # the preferred directions
diff --git a/compiler/modules/bank.py b/compiler/modules/bank.py
index af14c0ca..12fcb6dd 100644
--- a/compiler/modules/bank.py
+++ b/compiler/modules/bank.py
@@ -9,7 +9,7 @@ import debug
 import design
 from sram_factory import factory
 from math import log, ceil
-from tech import drc
+from tech import drc, layer
 from vector import vector
 from globals import OPTS
 
@@ -879,9 +879,16 @@ class bank(design.design):
         column_mux_pins = [self.port_data_inst[port].get_pin(x) for x in sel_names]
         
         route_map = list(zip(decode_pins, column_mux_pins))
+        if "li" in layer:
+            stack = self.li_stack
+            directions = "nonpref"
+        else:
+            stack = self.m1_stack
+            directions = "pref"
         self.create_vertical_channel_route(route_map,
                                            offset,
-                                           self.m1_stack)
+                                           stack,
+                                           directions=directions)
 
     def add_lvs_correspondence_points(self):
         """